The present invention relates, in general, to covers formed of welded metal plates for propeller or Kaplan type turbines or other similarly shaped pumps of the type shown in U.S. Pat. No. 1,779,191.
Generally, certain components for pumps and water turbines have been of cast construction. However, casting is a time consuming and expensive process. A number of schemes have attempted to overcome the problems inherent with casting, such as that shown in Federal Republic of Germany Patent No. 876 230, which utilizes a cover comprised of framework construction, having numerous cavities and a plurality of shells having the shape of conical envelopes with rings connecting them to each other in conjunction with filler plates. However, this still requires considerable expense for the machining of the connecting rings as well as extensive welding.
Another attempt to overcome this problem may be found in Japanese Patent Publication No. 57-2473 (A), which consists of numerous individual parts which are combined to form a framework construction which is generally hollow in cross section. However, this cover arrangement can only be manufactured through the use of substantial labor which is again expensive.